Carbon fiber and carbon matrix (C/C) composites are used in the aerospace industry to manufacture aircraft brake heat sink materials, among other applications. Similarly, silicon carbide (SiC) based ceramic matrix composites (CMCs) are also used as suitable aircraft brake materials, as well as within other industries, too (e.g., automotive, locomotive, engines, etc.). In various embodiments, CMC composites are produced using, for example, chemical vapor infiltration (CVI) and/or chemical vapor deposition (CVD) processes. Referring generally, CVI and CVD processes place substrates (e.g., porous preforms) into reactor furnaces and introduce gaseous precursors to form SiC depositions within the pores of the substrates. The SiC may be deposited in a series of one or more infiltrations coatings, including whereby the substrates are densified with carbon or other constitutents and then with SiC, or with SiC and then carbon or other constitutents. This collective process is generally referred to as chemical vapor densification.
In various CVI and CVD densification processes, by-product deposits accumulate within various components of CMC manufacturing systems, such as within their exhaust piping and/or plumbing systems. Since the by-product deposits can be reactive, and even pyrophoric, various precautions are undertaken to promote safe manufacturing environments. For example, conventional CMC manufacturing systems are shut down for lengthy periods of time while operators manually clean the components and piping to remove the by-product deposits. However, since these cleaning procedures involve shutting down the CMC manufacturing systems for periods of time, they decrease the systems' capacities and throughputs. In addition, build-up of condensable hydrocarbon tars from conventional carbon CVI and CVD processes, although not pyrophoric in nature, can also cause unintended reactions within various CMC manufacturing systems.
SiC deposition commonly uses methyltrichlorosilane (MTS) as a source chemical. By-products from decomposing MTS, however, include the afore-mentioned pyrophoric condensates, as well as hydrochloric acid. These caustic effluents require suitable mitigation, and eliminating and/or reducing them increases CMC manufacturing systems' and/or methods' throughput, among other benefits. In addition, unused hydrocarbon reaction exhaust and other gases (effluent) can be burned off and/or used to power an externality. Also, reducing processing time and waste can reduce the costs of production and the emission of greenhouse gases.